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CLC number: X77

On-line Access: 2015-02-03

Received: 2014-07-04

Revision Accepted: 2014-10-13

Crosschecked: 2015-01-23

Cited: 10

Clicked: 2794

Citations:  Bibtex RefMan EndNote GB/T7714

 ORCID:

Pei-wang Zhu

http://orcid.org/0000-0002-9892-0141

Zheng-lun Shi

http://orcid.org/0000-0002-3344-2943

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Journal of Zhejiang University SCIENCE A 2015 Vol.16 No.2 P.161-169

http://doi.org/10.1631/jzus.A1400195


Aluminum extraction from coal ash by a two-step acid leaching method


Author(s):  Pei-wang Zhu, Hua Dai, Lei Han, Xiu-lin Xu, Le-ming Cheng, Qin-hui Wang, Zheng-lun Shi

Affiliation(s):  State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China

Corresponding email(s):   szl@zju.edu.cn

Key Words:  Coal ash, Aluminum dissolution, Acid leaching, Roasting


Pei-wang Zhu, Hua Dai, Lei Han, Xiu-lin Xu, Le-ming Cheng, Qin-hui Wang, Zheng-lun Shi. Aluminum extraction from coal ash by a two-step acid leaching method[J]. Journal of Zhejiang University Science A, 2015, 16(2): 161-169.

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author="Pei-wang Zhu, Hua Dai, Lei Han, Xiu-lin Xu, Le-ming Cheng, Qin-hui Wang, Zheng-lun Shi",
journal="Journal of Zhejiang University Science A",
volume="16",
number="2",
pages="161-169",
year="2015",
publisher="Zhejiang University Press & Springer",
doi="10.1631/jzus.A1400195"
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%0 Journal Article
%T Aluminum extraction from coal ash by a two-step acid leaching method
%A Pei-wang Zhu
%A Hua Dai
%A Lei Han
%A Xiu-lin Xu
%A Le-ming Cheng
%A Qin-hui Wang
%A Zheng-lun Shi
%J Journal of Zhejiang University SCIENCE A
%V 16
%N 2
%P 161-169
%@ 1673-565X
%D 2015
%I Zhejiang University Press & Springer
%DOI 10.1631/jzus.A1400195

TY - JOUR
T1 - Aluminum extraction from coal ash by a two-step acid leaching method
A1 - Pei-wang Zhu
A1 - Hua Dai
A1 - Lei Han
A1 - Xiu-lin Xu
A1 - Le-ming Cheng
A1 - Qin-hui Wang
A1 - Zheng-lun Shi
J0 - Journal of Zhejiang University Science A
VL - 16
IS - 2
SP - 161
EP - 169
%@ 1673-565X
Y1 - 2015
PB - Zhejiang University Press & Springer
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DOI - 10.1631/jzus.A1400195


Abstract: 
To improve aluminum extraction efficiency, a two-step acid leaching process was proposed to dissolve aluminum and aluminum-bearing crystals with sulfuric acid. The first leaching residue (FLR) was obtained through direct leaching of coal ash with sulfuric acid. After roasting a mixture of the FLR and sodium carbonate, the aluminum-bearing crystals in FLR were completely destroyed while sodium silicate was generated. Then the roasted products were leached with water to dissolve the sodium carbonate. X-ray diffraction (XRD) analysis indicated that the water leaching residues (WLR) mainly contained the amorphous phase, which allowed easy aluminum extraction in the second leaching step. In the first leaching test with 10 mol/L sulfuric acid at 120 °C in 2 h and a solid to liquid ratio (S/L) of 1:2, aluminum dissolution from raw coal ash reached 81.72%. In the second leaching step with 5 mol/L sulfuric acid, the aluminum dissolutions from WLR were 87.31% at 20 °C and 99.06% at 100 °C. Total aluminum dissolutions were more than 97%. Moreover, the leaching process produced two by-products, sodium silicate solution and amorphous silicon dioxide, which contained nearly all the silicon from the coal ash.

二次酸浸法提取煤灰中的氧化铝

目的:煤灰渣酸浸提铝通常效率不高,主要因为灰渣中存在含铝晶体矿物(如莫来石、尖晶石和长石等)。为解决含铝晶体不易与硫酸反应的问题,本文提出二次酸浸提铝法。
创新点:基本实现铝硅分离,第一步酸浸实现非晶态铝的浸出,残渣经焙烧和水浸后,第二步酸浸实现剩余铝的浸出。
方法:1. 一次酸浸时,硫酸直接与煤灰渣反应浸出部分氧化铝,提铝残渣加碳酸钠焙烧后,含铝晶体遭到破坏;2. 焙烧产物经水浸溶解出硅酸钠,水浸残渣做X射线衍射分析表明其主要为铝硅非晶体活性物质,此时可用硫酸在温和条件下浸出剩余的铝。
结论:1. 一次酸浸提铝在10 mol/L硫酸、120 °C、2 h和1:2固液比的条件下,铝浸出率为81.72%;2. 用5 mol/L硫酸二次酸浸时,20 °C下铝浸出率已经达到87.31%,100 °C下更是达到99.06%;3. 综合两次酸浸结果,铝的浸出总效率在97%以上。

关键词:煤灰;氧化铝;酸浸;焙烧

Darkslateblue:Affiliate; Royal Blue:Author; Turquoise:Article

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